Automatically Change Heroku Accounts for Different Projects

.cdrc

heroku accounts:set ACCOUNT_NAME

.profile

    __load_cdrc() # called from .rvm/scripts/cd
    {   
      local working_dir
      working_dir="${1:-"$PWD"}"
      if [[ -f "$working_dir/.cdrc" ]]; then
          echo "Loading .cdrc..."
          source "$working_dir/.cdrc"
      fi
    } 

.rvm_scripts_cd

      __rvm_after_cd()
      {
        rvm_hook="after_cd"
        source "${rvm_scripts_path:-"$rvm_path/scripts"}/hook"
        #__rvm_unset_exports
        if type -t __load_cdrc -eq 'function' > /dev/null; then
            __load_cdrc
        fi  
      }

Requires that you first install the Heroku Accounts plugin (https://github.com/ddollar/heroku-accounts) and add an account to the plugin (heroku accounts:add ACCOUNT_NAME). After setting this up, you can create a .cdrc file in any directory which will be run as a shell script upon entering that directory. One pitfall is that the .cdrc file also loaded after running cd .. which is often unnecessary.

1. Modify .rvm/scripts/cd to call a __load_cdrc function if it has been defined. Find the __rvm_after_cd function and add the last three lines in the function as shown above.
2. Define the __load_cdrc function in ~/.profile to load a .cdrc file in the current directory if it exists.
3. Inside the directory for a Heroku app, create a .cdrc file including the following line.